Just wanted to add my welcome to the forum.
I guess I would just give it awhile for your husband to get used to you "having crushes," before trying to take anything to the next level. Maybe it's difficult right now, but sometimes time makes things easier.
It's a shame that your husband hasn't found any dates of his own. Maybe there's some kind of social situation he could try, just get used to being friends with people? A club, dealing with some kind of interest he has, something like that?
Is there anything you can do to "add extra spark" in your marriage? Anything missing? Sometimes if something's been missing for a long time, we just don't notice it.
I hope your interactions on Polyamory.com will help give you some ideas.
Love means never having to say, "Put down that meat cleaver!"